TWI713939B - Contact probe for a testing head for testing electronic devices - Google Patents

Abstract

A contact probe (10) for a testing head for testing electronic devices comprises a rod-like body (10’), which is made of a first conductive material and extends along a longitudinal axis (H-H), and a contact tip (11) supported by the body (10’) at an end portion (10a) thereof, the contact tip (11) being made of a second conductive material that is different from the first conductive material of the body (10’), the contact tip (11) comprising a contact zone (11c) adapted to perform the mechanical and electrical contact with contact pads of a device under test, wherein the body (10’) and the contact tip (11) comprise respective contact surfaces being in contact with each other. Suitably, the contact surfaces are complementary to each other and are shaped so as to comprise respective connection elements engaging each other, such connection elements being in the form of at least one protruding element (13p) projecting from the contact surface of one among the body (10’) and the contact tip (11), and in the form of at least one respective recess (13r) made in the other among the body (10’) and the contact tip (11)

Description

Contact probe for testing head of electronic device

The present invention relates to a contact probe for testing a test head of an electronic device integrated on a semiconductor wafer. The following disclosure refers to applications in this field, and the main goal is to simplify its description.

As everyone knows, the probe head or the test head is essentially an electronic device used to electrically connect the contact pads of multiple microstructures, especially the electronic device integrated on the semiconductor wafer to test the channel corresponding to the equipment To perform test functions, especially electrical tests or general tests.

Testing on integrated circuit devices is particularly helpful for detecting and isolating defective components as early as possible in the manufacturing process. Normally, probe heads are usually used for electrical testing of integrated circuit devices on wafers before cutting and packaging.

Generally speaking, the probe head includes a high number of contacts or contact probes, which are formed of a special alloy with good electrical and mechanical properties, and provide at least one contact portion for the corresponding device under test. A contact pad.

The so-called "vertical probe head" essentially includes a plurality of contact probes placed on at least a pair of substantially flat plate members or guides that are parallel to each other. These guides have suitable multiple Holes, and leave free space or air gap for the movement or possible deformation of the contact probes, then the guides are arranged at a certain distance from each other. In particular, a pair of guides includes an upper guide and a lower guide, both of which have a guide hole for sliding the contact probe in the axial direction, and are usually made of a special alloy wire with good electrical and mechanical properties. constitute.

The good connection between the contact probes and the contact pads of the device under test is ensured by pressing the probe head on the device itself. In the press contact, the contact probes (which can be Move in the guide holes formed by the upper guides and the lower guides) bend in the air gap between the two guides, and slide in the guide holes.

In addition, the bending of the contact probes in the air gap can be reduced by the proper configuration of the probes themselves or their multiple guides, as shown in FIG. 1, where, in order to simplify the description, the multiple contact probes A particular contact probe in the probe usually includes a probe head as shown in the figure, which is in the form of a so-called translation plate.

In particular, FIG. 1 schematically shows that a probe head 1 includes at least one upper plate member or guide member 2 and a lower plate member or guide member 3, each of which has a plurality of upper plates capable of allowing at least one contact probe 4 to slide. Guide hole 2a and a plurality of lower guide holes 3a.

The contact probe 4 has at least one end point or contact tip 4a. The term end or tip here or below refers to an end point, which is not necessarily sharp. In particular, the contact tip 4a is engaged on the contact piece 5a of a device under test 5, and performs mechanical and electrical contact between the device and a test equipment (not disclosed), wherein the probe head Form a terminal element.

In some examples, the heads of the contact probes themselves are fixedly fastened to the upper guide: these probe heads are called "resistive probe heads". Or, these probe heads are used with non-resistive probes, which means that the probes are not fixedly fastened, but are supported on a board through a micro-contact plate: These probe heads are called "non-resistive probe heads". The micro-contact plate is usually called a "spatial converter" because, in addition to contacting the probes, it also allows the spatial redistribution of the contact pads formed on the device under test, especially The restriction on the distance between the center positions of the cushions themselves is relaxed.

In this example, as shown in FIG. 1, the contact probe 4 has a contact tip 4 b, which is actually called a “contact head”, and faces a plurality of contact pads 6 a of the space converter 6. The guarantee of good electrical contact between the probe and the space transformer is similar to that by pressing the contact heads of the contact probes 4 on the contact pads 6a of the space transformer 6 to make contact with the The device under test touches.

The upper guide 2 and the lower guide 3 are separated by an air gap 7, thereby allowing the contact probes 4 to deform in the air gap 7, and ensuring that the tips of the contact probes 4 and the contact tips Each is in contact with the contact pads of the device under test 5 and the space converter 6.

The correct operation of a probe head is basically related to two parameters: vertical movement (or overtravel) and horizontal movement of the contact tip of the contact probe on the contact pad (or scrub). These features will be evaluated and corrected in the probe head manufacturing stage, because a good electrical connection between the probe and the device under test needs to be continuously ensured.

In addition, as the assembly density of modern probes integrated on the wafer increases, contact problems between adjacent probes are caused, especially when the test head is deformed during operation.

In order to ensure the correct orientation of the probe, in particular to ensure the direction of its deformed surface (and therefore its deformation), contact probes can be prepared by non-circular, especially triangular cross-sections, and by having individual non-circular, In particular, the guide plate of the triangular cross-section guide hole is used to prepare the test head, so that the contact probe can be fixed in place when it contacts the contact pad of the device under test (and when it deforms later).

In order to ensure that the probe is correctly moved between the guide holes, to ensure that the probe is fixed in the correct position in the guide plate, and to minimize the risk of probe clogging and the need to replace the probe head, those skilled in the art can The end of the contact probe 4 is coated with a conductive material layer to make it have a higher hardness than the conductive material in other parts of the contact probe.

Specifically, the coating extends over the terminal portion of each end, from the tip to the entire height of each via.

However, the high hardness of the conductive material also has obvious brittleness, and the thickness can only be reduced to prepare a film, for example, between 0.01 micrometer (μm) and 5 μm.

High-hardness conductive materials can also be used to prepare sheets that protrude from the end of the contact probe body. The sheet can penetrate the possible oxide layer covering the contact pad, so that the contact pad in other embodiments can contact bumps (that is, the conductive element protruding from the device under test as the contact portion). However, the sheet is very fragile and easily damaged, especially when force is suddenly applied.

The technical problem of the present invention is to provide a test head, which has a number of structural and functional characteristics of the contact probe, which can overcome the current limitations and defects that affect the technology in the field, and in particular can improve its end and each device under test Contact with the contact pad and avoid damage to its end.

The method for solving the problem of the present invention is to provide a contact probe, wherein the contact tip is all composed of conductive material and is different from the conductive material of the probe body supporting the tip, and has higher hardness in particular, wherein the probe body The outer shape of the contact surface with the contact tip is connected and complementary to each other to obtain an interlocking connection.

According to this solution, the aforementioned technical problem can be solved by a contact probe of a test head used to test electronic devices. The contact probe includes a cylindrical body composed of a first conductive material and extending along a length axis And a contact tip, supported by the body at its end, the contact tip is composed of a second conductive material that is different from the first conductive material of the body; the contact tip includes: a contact area for The contact pad of the device under test is mechanically and electrically contacted; wherein the body and the contact tip each include a contact surface to be in contact with each other, the contact surfaces are complementary to each other and their outer shapes each include a connecting element engaged with each other; and wherein the connecting element The form is: at least one protruding element protruding from the contact surface of one of the body and the contact tip; and at least one opposing recess formed by the other of the body and the contact tip, and the protruding element and the recess are mutually Cooperate, that is, fully pair with each other. In other words, the connecting elements are completely interlocked.

More specifically, the present invention further includes the following features, which can be applied individually or in combination.

According to an embodiment of the present invention, the maximum cross-sectional area of the contact tip is the same as the maximum cross-sectional area of the body.

According to an embodiment of the present invention, the protruding element and the concave portion have at least one arc-shaped portion.

According to an embodiment of the present invention, the contact tip includes at least one blunt part.

According to another embodiment of the present invention, the cross-sectional area of at least one part of the contact tip is smaller than the cross-sectional area of the corresponding body, and the cross-sectional area is obtained by measuring the cross-section perpendicular to the length axis.

According to another embodiment of the present invention, the contact tip includes a thin portion extending along the length axis and having a substantially constant cross-section corresponding to the extension of the contact area.

Specifically, the length of the detail measured along the length axis is between 30 μm and 600 μm.

In addition, the detail is aligned with the symmetry axis of the body.

According to another embodiment of the present invention, the first conductive material of the body is copper, and the second conductive material of the contact tip is selected from rhodium, palladium, iridium, platinum, or alloys thereof.

According to another embodiment of the present invention, the length of the protruding element measured along the length axis is between 10 μm and 100 μm.

According to another embodiment of the present invention, the contact area is only included in the contact tip.

According to another embodiment of the present invention, the contact tip is tapered.

Finally, the lateral cross-sectional area of the body and the contact tip are the same.

The present invention also relates to a test head for testing electronic devices. The test head includes: at least one guide plate with a plurality of guide holes, and the guide holes are respectively used for accommodating a plurality of contact probes, wherein at least one of the contact probes The probe is the contact probe described above.

The features and advantages of the contact probe and the test head of the present invention are detailed in the following non-limiting embodiments with reference to the drawings.

1: Probe head

2: Upper plate or guide

2A: Upper pilot hole

3: Lower plate or guide

3A: Lower guide hole

4: contact probe

4A: End point or contact tip

4B: Touch the tip

5: Device under test

5A: Contact

6: Space converter

6A: Contact pad

7: Air gap

10: Contact probe

10’: body

10a: end

10:wa wall

10: wb wall

11: Touch the tip

11c: contact area

12: area

13p: Protruding element

13r: recess

14: detail

F: Noodles

P1: Part One

P2: Part Two

Figure 1 schematically shows a contact probe housed in a test head of the prior art.

2A and 2B schematically show a front view and a perspective view of the contact probe, respectively.

3A and 3B schematically show perspective views of the contact probe.

Fig. 4 schematically shows a perspective view of the contact probe.

5A-5C schematically show perspective views of the contact probe of the present invention.

With reference to the drawings, the contact probes of the test head used to test the electronic device integrated on the semiconductor wafer are all schematically indicated by the symbol 10.

It should be noted that the drawings only represent schematic diagrams and are not drawn in actual size, and are only used to emphasize important features of the present invention. Furthermore, in the drawings, different elements are drawn schematically, and their appearances vary according to different applications. It should also be noted that the same component symbols in the drawings refer to components of the same appearance or function. Finally, the specific features of the embodiments in the drawings can also be applied to embodiments in other drawings.

As described in detail below, the contact probe 10 of the present invention can improve the mechanical and electrical contact between it and the contact pad of the device under test.

Specifically, the contact probe includes a cylindrical body 10' extending along a length axis H-H and made of a first conductive material, such as copper (Cu), but other conductive materials can also be used.

The body 10' extends between two ends, and supports a contact tip 11 connected to it at one of the ends (indicated by the symbol 10a). In other words, the end portion 10a of the main body 10' is the supporting portion of the contact tip 11.

The contact tip 11 is used to contact the contact pad of the device under test (not shown in the figure). More specifically, the contact tip 11 includes a contact area 11c for mechanically and electrically contacting the contact pad of the device under test.

Suitably, the contact tip 11 is made of a second conductive material different from the first conductive material of the body 10'. Specifically, the conductive material of the contact tip 11 is a high-hardness conductive material, such as rhodium (Rh). Obviously, other conductive materials can also be used to prepare the contact tip, such as palladium (Pd), iridium (Ir), and platinum (Pt), or alloys thereof.

In this way, the contact tip 11 of the contact probe 10 is a high-hardness element, which is supported by the end 10a of the body 10', and is used to mechanically and electrically contact the contact pad of the device under test via the contact area 11c .

According to the present invention, all contact with the contact pad of the device under test is performed by the contact tip 11, and the body 10' only serves as a mechanical support for the contact tip 11. In other words, only the high-hardness second conductive material forming the contact tip 11 directly contacts the contact pad of the device under test.

The body 10' and the contact tip 11 each include a contact surface for contacting each other; and, according to the present invention, the contact surfaces are preferably connected and complementary to each other, and their outer shapes each include connecting elements that engage each other.

The shape of the contact surface and the geometric appearance of the interface between the body 10' and the contact tip 11 can improve the mechanical support of the contact tip 11 and improve the overall performance of the contact probe 10.

Due to the shape of the contact surface, the contact area or interface between the body 10' and the contact tip 11 can thus be significantly increased. Specifically, the contact area is increased due to the presence of the connecting elements that are engaged with each other, and the connecting elements can also achieve an interlocking connection between the body 10' and the contact tip 11.

Suitably, the contact area between the body 10' and the contact tip 11 is greater than the cross-sectional area of the body 10', specifically greater than the maximum cross-sectional area of the portion of the body 10' that supports the contact tip 11, as detailed below .

Therefore, the interface between the body 10' and the contact tip 11 does not fall on a single cross-sectional plane, but, according to the present invention, falls on a preferred multi-faceted plane, wherein the body 10' and the contact tip 11 are in contact with each other. There are at least three noodles each.

In particular, the present invention provides the existence of connecting elements that are joined to each other to obtain a meshing effect between the body 10' and the contact tip 11.

According to the non-partial solution of the present invention, as shown in Figs. 2A-2B and 3A-3B, the contact surface of the body 10' and the contact tip 11 is stepped. In other words, the connecting element that implements the support of the contact tip 11 is a stepped shape of the contact surface of the body 10' and a stepped shape of the contact surface of the body 10' that engage with each other; the stepped shape of the contact surface of the body 10' has The geometric shape of the contact tip 11 is complementary to the geometric shape of the stepped contact surface. The number and size of the steps can vary, for example, according to the thickness of the contact tip 11 and/or the function of the material. Orders measured along the length axis H-H The length of the ladder is dimensioned to ensure a large amount of contact area between the body 10' and the contact tip 11, so that it has good support for the contact tip 11 and high resistance of the ladder type on the contact surface of the contact tip 11 On the other hand, it avoids the notching effect that limits the resistance of the contact tip 11. For example, the step type may have a length of about 10 μm.

The contact surface of the body 10' and the contact tip 11 can also have a triangular wave shape (as shown in FIG. 4), or a sawtooth wave shape or similar, wherein the contact surface of the body 10' can be matched and penetrate the The contact surface of the contact tip 11 is used to achieve the required interlock connection and support the contact tip 11.

Specifically referring to FIG. 2A, at least one cross-section of the contact tip 11 may be smaller than the corresponding cross-section of the body 10', and at least one surface F of the body 10' at its end 10a does not support the contact tip 11. Preferably, only one section (measured along the x-axis of the graphical coordinate system) is smaller than the corresponding section of the body 10'. Here, the cross-sectional area of the contact tip 11 in the contact region 11c is smaller than the maximum cross-sectional area of the body 10.

In this way, two parts of the body 10' can be defined: a first part P1 located under the surface F and not under the contact tip 11; and a second part P2 supporting the contact tip 11 and located under the latter. In other words, the first part P1 is a part of the main body 10', having a cross-section corresponding to the projection of the plane F on a plane perpendicular to the axis HH; and the second part P2 is a part of the main body 10' having a The cross section corresponds to the projection of the surface in contact with the contact tip 11 on a plane perpendicular to the axis HH.

The first portion P1 of the body 10' is located under the inclined surface F, so the contact tip 11 is not accommodated. The second part P2 of the body 10' supports the contact tip 11, and, as described above, the contact surface profile is used to make the contact area between the body 10' and the contact tip 11 larger than the second part The maximum cross-sectional area of P2. Here, the second part P2 is also referred to as a "support part".

In the specific solutions shown in FIGS. 2A-2B, 3A-3B, and 4, the body 10' of the contact probe 10 is tapered and includes a blunt portion or a cut portion. In particular, the blunt portion formed in the body 10' is the The wall 10wa of the main body 10' is opposite to the wall 10wb including the contact surface of the main body 10' and includes the surface F, which is inclined with respect to the longitudinal axis HH, specifically from the wall wa to the inner side of the main body 10' tilt.

The blunt part of the body 10' can be prepared at different positions along the length axis H-H.

In FIGS. 2A-2B, the inclined surface F is located at the end of the body 10', and one surface thereof directly contacts the contact tip 11.

Alternatively, as shown in FIGS. 3A-3B, the blunt portion of the body 10' may be located at a position where the inclined surface F does not directly contact the contact tip 11. Here, the body 10' includes a region 12 whose maximum cross-sectional area is smaller than the maximum cross-sectional area of the body 10'. The region 12 extends along the length axis H-H and forms the end 10a of the body 10'. Here, the contact tip 11 is completely supported by the region 12 of the body 10', and the contact region between the body 10' and the contact tip 11 is larger than the maximum cross-sectional area of the region 12, as described above.

Based on the needs and / or circumstances, the contact tip 11 of the maximum cross-sectional area may be between 500μm ² to 2500μm ^2.

Since the specific geometric shape of the interface between the contact tip and the body cannot ensure that the body and the tip maintain an effective linkage, the solutions disclosed in Figures 2A-2B, 3A-3B, and 4 are beneficial However, this technology still has a few shortcomings.

According to the present invention, as shown in FIGS. 5A-5C, the body 10' of the contact probe 10 does not include a blunt portion, and the maximum cross-sectional area of the contact tip 11 is the same as the maximum cross-sectional area of the body 10'. Therefore, according to the present invention, the cross-sectional area of the contact tip and the body are the same.

Specifically, the form of the connecting element is: a protruding element 13p protruding from the contact surface of one of the body 10' and the contact tip 11; and an opposite recess 13r formed by the other; the protruding element 13p The concave portion 13r and the concave portion 13r have a connected and complementary shape and are joined to each other.

The connecting elements of the present invention are completely interlocked, similar to a puzzle.

In the embodiment of FIGS. 5A and 5C, the protruding element 13p is included in the contact tip 11 and protrudes from its contact surface; and the recess 13r is included in the body 10'. Alternatively, in the embodiment of FIG. 5B, The protruding element 13p is included in the body 10' and protrudes from the contact surface thereof; and the recess 13r is included in the contact tip 11.

For example, the length of the protruding element measured along the length axis H-H is between 10 μm and 100 μm.

In a preferred embodiment of the present invention, the protruding element 13p and the recess 13r have at least one arc-shaped portion; in other words, at least part of it is curved, specifically at the end along the longitudinal axis H-H.

The contact tip 11 includes at least one blunt part to reduce the area of the contact area 11c.

Reducing the area of the contact tip 11 can reduce the possibility of the spread of two-sided fracture and the inherent defects of the contact tip 11, which usually occur in high-hardness metals.

If the contact tip 11 includes a blunt portion, according to the embodiment of FIGS. 5A-5B, the contact tip 11 also includes a thin portion 14 extending along the length axis HH and having substantially the same cross-sectional area corresponding to the extension of the contact region 11c, wherein The detail 14 does not contact any part of the body 10'. Therefore, the contact between the contact tip 11 and the contact pad of the device under test can be made easier. If the blunt part is not present, the detail can obviously also exist.

Appropriately, the size of the detail 14 can be designed as a so-called "wearable" tip, which can withstand a variety of deformation operations and increase the service life of the corresponding contact probe and the test head including it.

Preferably, if the thin portion 14 is provided, it (and the contact area 11c) can be aligned with the symmetry axis of the body 10'; therefore, in a preferred embodiment, the thin portion is located at the center.

The length of the detailed portion 14 measured along the length axis H-H is between 30 μm and 600 μm, preferably 200 μm, which can be changed according to requirements or conditions. Generally speaking, the length of the interface between the main body 10' and the contact tip 11 is projected along the direction parallel to the longitudinal axis H-H, which is equivalent to the length of the thin portion 14.

The body 10' and the contact tip 11 have at least one same cross-sectional area (generally a smaller cross-sectional area), measured along the y-axis of the graphical coordinate system and between 25μm and 60μm. The cross-sectional area can be adjusted according to requirements /Or the situation changes, for example, according to the electrical contact function implemented by the contact tip 11.

In any case, according to the present invention, the contact area between the body (that is, the support of the tip) and the tip should preferably be larger than the maximum cross-sectional area of the body and the tip itself. In other words, the contact area between the body 10' and the contact tip 11 is larger than the projected area of the contact surface on a plane perpendicular to the H-H axis.

According to the present invention, the matching between the protruding element 13p and the recess 13r preferably ensures good support of the contact tip 11. The protruding element 13p serves as a needle for fixing the tip, wherein the projection of the contact surface is the same as the largest cross-sectional area of the body.

The contact with the pad of the device under test is all performed by the contact tip 11. Due to the specific geometric shape of the contact surface, it is properly supported by the body 10'.

Therefore, it can be clearly seen that the contact tip 11 of the present invention is less prone to damage and can be used to block high shear and compression forces.

Furthermore, the detail 14 can be simply prepared as a symmetrical shape along the length axis of the contact probe, which simplifies the structure of the test head and also makes a real "consumable" tip.

As mentioned above, the contact probe 10 described in this specification is used to house a test head for testing electronic devices to improve the performance of the test head. For example, the test head may include at least one guide plate with a plurality of guide holes, and the contact probe of the present invention slides axially in the guide holes, but other solutions of the test head can also be used.

In summary, the present invention provides a contact probe, in which the contact tip and the probe body supporting the tip are made of different conductive materials. In particular, the material has high hardness, and the probe body and the contact tip are The outer shape of the contact surface joins and complements each other to obtain a structure of interlocking connection.

According to the present invention, the shape of the interface between the probe body and the contact tip is better to ensure that the contact tip is better supported, so that the overall contact probe has better performance. In this way, the contact probe can have a contact tip made of a high-hardness material, which solves the problem of contact tip support without resorting to the coating part.

Therefore, the technical problem of the present invention can be appropriately solved by the geometrically complementary mechanical pairing between the probe body and the contact tip, wherein the contact surface includes parts that fit and penetrate each other. The aforementioned pairing can ensure the mechanical support required for the contact probe .

The adopted geometric appearance can increase the contact area, so increase the number of connections between the probe body and the contact tip, and ensure that the force is transmitted to the probe body in different directions without causing structural damage to the contact tip, so that the tip can resist Various pressures from the probe. Therefore, it can be observed that the highest resistance is achieved when the contact surface undergoes normal compression.

In particular, if the contact probe is prepared by directly growing on the body (for example, electroplating), the growth parameters can be used to create the tensile state of the contact tip and the corresponding interface compression to ensure better subsequent pressure resistance.

Finally, the presence of contact tips made of high-resistance conductive materials (such as rhodium) can improve the reliability of electrical contacts, reduce the cleaning cycle, eliminate possible tip activation after the resting period, and reduce tip consumption and extend its service life.

Therefore, the above advantages result in improved performance of the contact probe of the present invention.

Obviously, those with ordinary knowledge in the technical field of the present invention can implement various changes or modifications to the aforementioned contact probes and test heads according to specific requirements or specifications, all of which are covered by the scope of the invention patent application defined by the claims.

10: Contact probe

10’: body

10a: end

11: Touch the tip

11c: contact area

13p: Protruding element

13r: recess

14: detail

Claims (14)

A contact probe (10) for a test head for testing electronic devices. The contact probe (10) comprises: a cylindrical body (10') composed of a first conductive material and along a length axis (HH) Extension; and a contact tip (11) at its end (10a) supported by the body (10'), the contact tip (11) is made of one of the first conductive materials different from the body (10') The contact tip (11) includes: a contact area (11c) for mechanically and electrically contacting the contact pad of the device under test; wherein the body (10') and the contact tip (11) Each includes a contact surface to be in contact with each other, the contact surfaces are complementary to each other and their outer shapes each include a connecting element engaged with each other; and the form of the connecting element is: at least one protruding element (13p) protruding from the body (10' ) And the contact surface of one of the contact tip (11); and at least one opposite recess (13r), which is formed by the other of the body (10') and the contact tip (11); the contact tip (11) The maximum cross-sectional area is the same as the maximum cross-sectional area of the body (10'). The contact probe (10) according to claim 1, wherein the protruding element (13p) and the concave portion (13r) have at least one arc-shaped portion. The contact probe (10) according to claim 1, wherein the body (10') includes at least one blunt part. The contact probe (10) according to claim 1, wherein the cross-sectional area of at least one part of the contact tip (11) is smaller than the cross-sectional area of the corresponding body (10'), and the cross-sectional area is measured along the longitudinal axis (HH) section. The contact probe (10) according to claim 4, wherein the contact tip (11) includes a detail (14) extending along the length axis (HH) and having a substantially constant cross-section, corresponding to the contact area (11c) ) Of the extension. The contact probe (10) according to claim 5, wherein the length of the detail (14) measured along the length axis (H-H) is between 30 μm and 600 μm. The contact probe (10) according to claim 5, wherein the detail (14) is aligned with the symmetry axis of the body (10'). The contact probe (10) according to claim 1, wherein the first conductive material of the body (10') is copper. The contact probe (10) according to claim 1, wherein the second conductive material of the contact tip (11) is selected from rhodium, palladium, iridium, platinum, or alloys thereof. The contact probe (10) according to claim 1, wherein the length of the protruding element (13p) measured along the length axis (H-H) is between 10 μm and 100 μm. The contact probe (10) according to claim 1, wherein the contact area (11c) is only included in the contact tip (11). The contact probe (10) according to claim 1, wherein the contact tip (11) is tapered. The contact probe (10) according to claim 1, wherein the transverse area of the body (10') and the contact tip (11) are the same. A test head for testing electronic devices, the test head comprising: at least one guide plate with a plurality of guide holes, the guide holes are respectively used for accommodating a plurality of contact probes, and at least one of the contact probes is requested The contact probe described in item 1.

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